Hyperpolarized xenon magnetic resonance imaging (MRI) offers potential as a new diagnostic research and clinical tool for animals and humans. Inhaled and in the gas phase, it can provide structural information about lungs. Due to its high solubility in blood and tissues, it can also provide functional images of lungs. As it is absorbed into the system, it can provide images of the cardiovascular system and highly perfused organs. Since xenon is lipophilic it offers particular promise as a contrast agent for the white matter of the brain, not distinguishable with present MRI techniques. The principal obstacle to exploiting this modality is low availability and quality of hyperpolarized gas. Researchers at the University of New Hampshire have extensive experience in hyperpolarization of noble gases. We have been polarizing 3He for nuclear physics experiments for over six years. One year ago, the UNH group joined a multi-disciplinary collaboration to apply their expertise to MRI studies. In this proposal, we describe a new approach to achieving a high degree of xenon hyperpolarization with a excellent gas polarization rate. We intend to implement a newly conceived component in the gas polarization process, as well as rigorously apply procedures of optimization. We propose to assemble, test, modify and improve a high capacity xenon polarizer to explore the range of variables in the polarization process, to test the hypothesis that our new design will yield large quantities of highly polarized xenon for MRI studies. Researchers at the Brigham and Women's Hospital have extensive experience in MRI, including hyperpolarized xenon MRI. We will perform initial MRI scans of phantoms and model tissues under this grant. We will also use the hyperpolarized xenon gas to perform more exhaustive studies of biological systems in the context of other grants under the full collaboration. Only with an abundant supply of hyperpolarized xenon will we be able to test the hypothesis that the routine availability of large quantities of xenon, hyperpolarized to a high degree, will lead to new advances in imaging.